Spark-plug.



F. BARTL.

SPARK PLUG. APPLIGATIOH FILED NOV.19, 1909.

1,023,493. Patented Apr. 16, 1912.

FRANZ BA'BTL, or NEW YORK, N. Y.

SPARK-PLUG.

Specification of Letters Patent.

Patented Apr. 16, 1912.

Application filed November 19, 1909. Serial No. 528,875.

To all whom it may concern:

Be it known that I, FRANZ BARTL, a subject of the Emperor of Austria-Hungary, and a resident of New York, in the county and State of New York, have invented certain new and useful Improvements in Spark-Plugs, of which the follow ing is a specification.

This invention has reference to improvements in spark-plugs and pertains particularly to that type which is used in igniting devices for explosive engines such as are employed in automobiles and the like.

The principal requirements for a desirable spark-plug from the standpoint of the chaufieur are that it is easily taken apart and cleaned. Certain parts, especially porcelain tubes are often broken when attempting to take the plug apart for the purpose of cleaning it.

It is the special object of the present invention to produce spark-plugs in which breakable parts, such as porcelain tubes are well protected and guarded against breakage when the plug is taken apart to be cleaned. This is accomplished by virtue of the novel construction of the plugs and this invention pertains to spark-plugs provided with enamel insulation as descnbed in Letters Patent of the United States No. 918,726, granted to me April 20, 1909.

The novel spark-plug further is so constructed that the pin forming one electrode and the porcelain tube surrounding same can not fall into the cylinder even if inclosing parts should break. By providing double insulation the danger of short circuits is eliminated if the porcelain tube should break. The method and means of scouring the porcelain tube are such as to prevent its brcakin by lateral pressure or expansion. In tlddltlOIl to these main objects it has been sought to keep the cost of production low by making the plug of relatively few parts and care has been taken to produce a durable and neat article, all as will be fully described hereinafter with reference to the accompanying drawings in which:

Figure 1 represents in longitudinal section a spark-plug which embodies in desirable form the present improvements, and Fig. 2 is a cross section of same on line 22 of Fig. 1.

Similar characters of reference denote like parts in all the figures.

On the drawing a re resents the shell which is referably ma e of cold drawn steel; it is liored out from both sides leaving inside an annular shoulder a. On the top of the shell there is an acute annular rim a integral therewith. The bottom portion of the shell is threaded on the outside and forms at the end inwardly a rim (1. The interior of the shell is lined with enamel lastingly produced thereon, which insulates it perfectly. y

Above the shell a there is a plug 6 of very tough insulating material, such as fiber or the like. The plug 3) is about as wide as the shell but its lower portion 6 is reduced to fit loosely in the upper portion of said shell. there is a circular channel 6 greatly reduced at the top as shown at 6 The wide portion of the plug is preferably made somewhat slanting toward the center from the shell upward.

A brass washer c of peculiar shape is provided in the top portion of the plug 1;. This washer is flush with the top surface of the plug and has an annular downward flange 0 sunk into the plug near its outer end. Centrally the washer has a circular portion a which fits the upper reduced channel or bore 6 of the plug and is threaded on the inside.

In the wide channel or bore 6 of the plug 6 there is the porcelain tube d which does not reach u to the end of same but extends downwar ly passing the inner annular shoulder a, of the shell and reaching to nearly the bottom end of same. The porcelain tube rests loosely in the plug and its lower portion is enlarged forming a broad shoulder al while its end is again of the regular width. The annular shoulder d of the tube (1 is near the bottom of the inner annular shoulder a of the shell and between both an annular elastic washer e is provided, preferably a copper gasket.

Within the porcelain tube there is an Centrally within the plug b iron rod f forming the inner electrode while the shell a forms the second electrode. The rod f has a threaded upper ortion f which passes through the inner threaded portion a of the peculiarly shaped washer 0. The remaining portion of the rod 1 is covered with insulating enamel. At the bottom end the rod is flanged out as shown at f This flange is flush with the annular inward rim a, of the shell and there is suflicient space between both to create a passage for the spark. On the inside the flange is provlded with an annular integral rim f adapted to receive the bottom end of the porcelain tube. To ease the tube an elastic washer g is inserted in said rim, said washer may be of asbestos or a copper gasket. To tighten the various parts of the plug a lock nut h is provided on the portion of the inner rod The various parts of the plug are easily assembled: First the reduced lower portion of the fiber plug is placed into the upper portion of the shell leaving an empty space below, then the porcelain tube with inner electrode is inserted from below and the threaded portion of the rod passed through the inner threaded portion of the peculiarly shaped top washer in the plug. Now the lock nut is applied and the device tightened. The acute annular rim a? of the shell cuts into the fiber of the plug and forms a tight closure or joint without using a washer thus saving same. This joint is much tighter than the joint formed by the washer e and both joints are a perfect seal against any oil. The porcelain tube, although tightened, is not strained because it rests against the elastic washers e, g and as above stated it is loosely mounted within the device and free at the top.- The peculiarly shaped washer in the top portion of the plug holds the same tightly and even if the plug should be smashed its broken parts will be held together by the inward rim 0 of same because the thread is in the washenand not in the plug. In case the lock nut is drawn too tightly no damage will result, the plug only will get tighter in the acute rim of the shell and the washers easing the porcelain tube will be a little more compressed, the tube itself is loose within and expansion and lateral pressure will not hurt it.

I claim as my invention:

1. In a spark plug for explosive engines having as one electrode a steel shell with an integral insulating refractory coating on the inside and an inner electrode with such coating on its outside surface, a sharp acute annular rim on the outer end portion of said shell, a tough insulating plug with a central bore reduced at the outer end engaging the sharp acute rim of the shell and having an inner reduced portion 'fitting loosely within same, a metal washer located centrally within the outer end of the plug having an inturned peripheral flange and an inwardly extending portion in the reduced outer end portion of the bore and threaded on the inside, an inner electrode with threaded outer end portion engaging the thread of the washer, and a lock nut.

2. In a spark plug for explosive engines, a steel shell with an acute annular rim at its outer end portion, an inner annular shoulder near its middle portion, and an inward rim at the inner eiid, a tough fiber plug with central bore engaging the acute rimiof the shell to form an oil-tight closure and having a reduced inner portion within the shell, a metal washer centrally within the outer end pf the plug and threaded inside, an inner electrode threaded to engage the metal washer, a porcelain tube with a shoulder bearing loosely on the inner electrode, an elastic washer between the shoulders of the shell and the porcelain tube, and means for tightening the device.

3. In a spark plug of the type described a steel shell with an acute annular rim formed at its outer end, a tough fiber plug having a reduced inner portion fitting loosely into the outer end portion of the shell and engaging said acute rim, an inner annular shoulder in the shell, an inner elec- 'trode with a flanged inner end portion, an

inwardly extending annular rim on said flange, a porcelain tube bearing loosely on the inner electrode extending partly into the plug and having on its inner portion an annular shoulder below the inner shoulder of the shell, an elastic washer between said shoulders, a second elastic washer within the inner rim of the inner electrode flange on which the porcelain tube rests, said acute annular rim and washer forming thus a tight closure, and means for tightening the device.

4. In a spark plug of the type described, a shell wit-h an inner annular shoulder near its middle portion, an inner electrode thread ed at the outer end and formed with an annular flange at the inner end with an anreduced outer end portion of the bore and an inner reduced portion extending into the shell, a metal washer located Centrally within the outer end of the plug provided with an inturned peripheral flange and a central inwardly extending portion in the threeded on the inside, an inner electrode passing through the washer, an outer elec- 10 N. Y., this 13th- Witnesses CORIINNE MYERS, JAMES H. Goeom. 

